SsangYong: Engine Euro 4. Service manual — part 27
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
33
2411
EXHAUST SYSTEM
D27DTP/D27DT (EU4) SM - 2006.08
D27DTP/D27DT (EU4)
ENGINE
FUEL
I
N
T
AKE
EXHAUST
PRE-HEA
TING
LUB
COOLING
SWITCHABLE
ECU
DIAGNOSIS
Throttle Body and Throttle Flap Actuator
For the vehicle equipped with CDPF, the throttle body is installed in the opening of intake manifold. The flap in the throttle
body is actuated by vacuum and the throttle body is operated only when the engine is idling (700 ~ 800 rpm) or running
at below 2500 rpm without accelerator pedal depressed. (For detailed operating range, refer to the control map.)
With EGR ratio and pressure difference provided by the differential pressure sensor, the ECU determines the CDPF’s
burning range. If the ECU determines to burn the soot in CDPF, it checks whether the engine is running in low load
range (engine idleing or running at below 2500 rpm without depressing the accelerator pedal). If the engine is running
in low load range, the flap in the throttle body is closed by vacuum modulator. The flap is not completely closed to
prevent engine from turning off.
In summary, the operating conditions for the flap in the throttle body are as follows:
Overview
Actuator for controllling
throttle flap
1. When the CDPF’s burning conditions are met (soot mass is over the limit and EGR ratio and tempera-
ture of exhaust gas are met with operating conditions)
2. When the engine is running in low load range (idling (700 ~ 800 rpm) or running at below 2500 rpm
without accelerator pedal depressed)
It controls the flap in the throttle body.
Vacuum actuated:
Throttle flap closed
→ Vacuum pressure at approx. 680
~ 720 hpa (intake air volume decreased)
Vacuum released (atmospheric pressure actuated):
Throttle flap opened
→ Atmospheric pressure actuated
(normal amount of intake air supplied)
Vacuum Modulator for Controlling Throttle Flap
Throttle body and throttle flap actuator
• The flap in the throttle body is operated only when the engine is running in low load range. It is to
increase the temperature of exhaust gas by decreasing the amount of intake air and increasing the
amount of fuel supplied since the fuel including post injected fuel is not enough to increase the tem-
perature up to the CDPF's burning temperature.
NOTICE
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
34
2411
EXHAUST SYSTEM
D27DTP/D27DT (EU4) SM - 2006.08
D27DTP/D27DT (EU4)
• Housing material: AC4C (Gravity Casting)
• Response: OPEN
→ CLOSE: approx. 200 msec, CLOSE → OPEN: approx. 200 msec
• Operating distance of actuator by vacuum pressure
Below approx. 0.5 mm when the vacuum pressure is at P1 (approx. -110 mbar)
Below approx. 25 mm when the vacuum pressure is at P2 (approx. -750 mbar)
• Leak limit of actuator diaphram: Below 0.15 litre/min. (at -500 mbar)
Throttle body housing
Sealing cap
Snap ring
Bush
Shaft
Flap bolt
Oil seal
Washer
Bracket
Actuator’s vacuum actuated
(approx. 680 ~ 720 hpa)
→ CLOSE
Actuator’s vacuum released
(atmospheric pressure actuated) - OPEN
Vacuum actuator
EGR valve
installation side
Specifications
Structure and Components
Vacuum port
Actuator operating rod
Actuator load’s
moving distance
when the
actuator’s vacuum
is actuated: 25 mm
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
35
2411
EXHAUST SYSTEM
D27DTP/D27DT (EU4) SM - 2006.08
D27DTP/D27DT (EU4)
ENGINE
FUEL
I
N
T
AKE
EXHAUST
PRE-HEA
TING
LUB
COOLING
SWITCHABLE
ECU
DIAGNOSIS
Vacuum Modulator
As the vacuum modulator for controlling throttle body flap has been added, three vacuum modulators are installed in total.
As one vacuum modulator is added, the existing modulators’ shape have changed.
1. Vacuum modulator for controlling turbocharger wastegate (shape changed)
2. Vacuum modulator for controlling EGR valve (shape changed)
3. Vacuum modulator for controlling throttle flap (added - only for vehicle with CDPF)
The vacuum modulator systems differ in D27DT engine, D27DTP (POWER UP) engine and D27DT engine with
CDPF. For more details, refer to the appropriate section.
D27DT Engine Vacuum Modulator (without CDPF)
Vacuum modulator for
controlling VGT turbocharger
wastegate
Vacuum Modulators by Engine
EGR valve
Throttle flap actuator
Throttle flap
D27DTP (POWER UP) Engine Vacuum Modulator
Vacuum modulator for
controlling throttle flap
Vacuum modulator for
controlling EGR valve
Vacuum modulator for controlling
turbocharger wastegate
TO turbo-
charger
Actuator
From vacuum
pump
To EGR valve
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
36
2411
EXHAUST SYSTEM
D27DTP/D27DT (EU4) SM - 2006.08
D27DTP/D27DT (EU4)
The vacuum modulator for controlling throttle body is controlled by ECU when the CDPF’s burning conditions are
met and the engine is running in low load range (idling or running at below 2500 rpm without accelerator pedal
depressed). There is no change for other vacuum modulators.
Vacuum modulator for vehicle equipped with CDPF
Vacuum input
(From Vacuum pump)
Vacuum output
(Throttle flap)
Connector
Inner plunger
Conventional vacuum modulator for D27DT
For internal structure, refer to the figure below.
Structure and Operating Principle Vacuum Modulator
Vacuum pump
Output vacuum
Ambient air
Plunger
Connector
Normal state (A)
Diaphram
Plunger
Spring
Seat assembly
Atmospheric pressure
Vacuum control
Air flow
Duty increased (B)
Duty decreased (B)
* The vacuum is adjusted according to the relation between the pressure of nipple
cover chamber (I) and magnetic force (II).
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